Filler, method for producing filler, and water treatment method

Abstract

The embodiment of the application discloses a kind of fillers, the preparation method of filler and water treatment method, filler includes the elemental sulfur and ferrous sulfide of mass ratio (1.5~3) is 1;Filler is when the reactor of microbial carrier handles low concentration nitrate nitrogen sewage, stable realization short denitrification, realize the accumulation of nitrite nitrogen, and can be synchronized phosphorus removal;Through combined anaerobic ammonia oxidation process, the efficient denitrification of low concentration nitrogen-containing wastewater is realized;The filler can realize stable short denitrification under normal conditions, easy to operate, control simple, without controlling sewage to maintain higher pH, free ammonia and free nitrous acid nitrogen and other conditions;Nitrite nitrogen produced in the process of realizing short denitrification using the filler of the application can be combined with anaerobic ammonia oxidation process to further remove ammonia nitrogen in sewage;While obtaining suitable concentration ammonia nitrogen and nitrate in tail water of sewage plant, the aeration quantity and external carbon source dosage of front section treatment process of sewage plant are reduced.

Description

Technical Field

[0001] This application relates to the field of water treatment technology, and in particular to a packing material, a method for preparing the packing material, and a water treatment method. Background Technology

[0002] Eutrophication of water bodies has long been a serious environmental problem both domestically and internationally, and reducing the input of nitrogen and phosphorus is key to controlling this problem. Currently, the effluent from urban wastewater treatment plants still contains high concentrations of total nitrogen and total phosphorus, far exceeding the limits that lead to eutrophication of natural water bodies. Furthermore, with the gradual increase in national water quality requirements, wastewater discharge standards are constantly being raised, making advanced treatment of effluent a common approach to upgrading wastewater treatment plants. Anaerobic ammonia oxidation is currently a research hotspot in nitrogen removal technology, offering high nitrogen removal efficiency, low sludge production, and no need for external organic carbon sources. However, its application in effluent is limited because the key reaction substrate, nitrite nitrogen, is difficult to stably obtain in low-concentration nitrogen-containing effluent. Short-cut nitrification (converting ammonia nitrogen to nitrite nitrogen) and short-cut denitrification (converting nitrate nitrogen to nitrite nitrogen) are the main treatment technologies for obtaining nitrite nitrogen, but they are difficult to stably achieve in low-concentration nitrogen-containing effluent. Sulfur autotrophic denitrification is a nitrogen removal method that uses inorganic sulfur as an electron donor. It offers good nitrogen removal efficiency and reduces costs. Elemental sulfur is a commonly used electron donor, being inexpensive and easy to operate. However, achieving elemental sulfur autotrophic short-cut denitrification is challenging. A few studies have focused on high-concentration nitrate-containing wastewater, achieving nitrite nitrogen accumulation by controlling pH, free ammonia, and free nitrite nitrogen. However, for low-concentration effluent, short-cut denitrification remains difficult to achieve. Summary of the Invention

[0003] Therefore, it is necessary to provide a packing material, a method for preparing the packing material, and a water treatment method that can stably achieve short-cut denitrification of wastewater containing low concentrations of nitrate nitrogen.

[0004] A filler comprising: elemental sulfur and ferrous sulfide in a mass ratio of (1.5 to 3):1.

[0005] A method for preparing a filler includes the following steps:

[0006] S01. Mix elemental sulfur and ferrous sulfide powder in a mass ratio of (1.5 to 3):1 until homogeneous to obtain a powder mixture;

[0007] S02. Sinter the powder mixture at 115-150°C for 20-30 minutes until the elemental sulfur is in a molten state and uniformly coated with the ferrous sulfide;

[0008] S03. The sintered molten filler is physically granulated and cooled to solidify to form the filler.

[0009] In one embodiment, the physical granulation method includes any one of die extrusion cooling, rotary steel strip condensation granulation, tower air cooling granulation, direct water cooling granulation, and spray granulation.

[0010] A water treatment method includes the following steps:

[0011] Provide the above-mentioned packing material;

[0012] The packing material is placed in the reactor, and then activated sludge is inoculated into the reactor to enrich and cultivate sulfur autotrophic denitrifying bacteria, or denitrifying sludge containing sulfur autotrophic denitrifying bacteria is directly inoculated so that the sulfur autotrophic denitrifying bacteria attach to the surface of the packing material.

[0013] Wastewater to be treated is injected into the reactor so that sulfur-autotrophic denitrifying bacteria attached to the packing surface can use the packing as an electron donor to perform short-cut denitrification of the wastewater, converting nitrate nitrogen in the wastewater into nitrite nitrogen, thereby achieving the accumulation of nitrite nitrogen.

[0014] During the short-range denitrification process, the ferrous ions released from the ferrous sulfide in the packing material or the ferric ions generated form precipitates with orthophosphate in the wastewater, thereby removing total phosphorus from the wastewater.

[0015] In one embodiment, it further includes:

[0016] Wastewater treated by short-cut denitrification is subjected to anaerobic ammonia oxidation treatment. Under the action of anaerobic ammonia oxidizing bacteria, the nitrite nitrogen accumulated in the wastewater after short-cut denitrification and the ammonia nitrogen in the wastewater are simultaneously converted into nitrogen gas, so as to achieve efficient denitrification of low-concentration nitrogen-containing wastewater.

[0017] In one embodiment, the concentration ratio of ammonia nitrogen to nitrate nitrogen in the wastewater influent is 1:(1.5-2).

[0018] In one embodiment, the water treatment method includes a one-stage combined process or a two-stage combined process;

[0019] The single-stage combined process refers to: short-cut denitrification and anaerobic ammonia oxidation treatment of wastewater in the same reactor; short-cut denitrification converts nitrate nitrogen in wastewater into nitrite nitrogen, which is then removed together with ammonia nitrogen by anaerobic ammonia oxidation, achieving efficient nitrogen removal in the same reactor;

[0020] The two-stage combined process refers to the following: wastewater is treated by short-cut denitrification and anaerobic ammonia oxidation in two reactors connected along the influent direction. The two reactors are defined as a short-cut denitrification reactor and an anaerobic ammonia oxidation reactor, respectively. The effluent from the short-cut denitrification reactor flows into the anaerobic ammonia oxidation reactor for anaerobic ammonia oxidation treatment, thereby achieving efficient nitrogen removal.

[0021] In one embodiment, in the single-stage combined process, anaerobic ammonia oxidation sludge is simultaneously inoculated in the same reactor, or auxiliary packing material loaded with anaerobic ammonia oxidation sludge is added, or anaerobic ammonia oxidation bacteria are enriched through domestication cultivation.

[0022] In one embodiment, the auxiliary filler is any one of sponge, ceramsite, suspended filler, braided biological filler, geotextile, mesh, and volcanic rock.

[0023] In one embodiment, in the two-stage combined process, the anaerobic ammonia oxidation reactor includes any one of a packed bed, a fluidized bed, a contact oxidation reactor, an MBR reactor, and an MBBR reactor.

[0024] The filler in this application has at least the following beneficial effects:

[0025] 1. This packing material, acting as an electron donor, stably achieves short-cut denitrification of low-concentration nitrate nitrogen and enables the accumulation of nitrite nitrogen;

[0026] 2. By combining anaerobic ammonia oxidation processes, efficient denitrification of low-concentration nitrogen-containing wastewater was achieved, providing a new and efficient solution for denitrification of wastewater treatment plant effluent;

[0027] 3. This packing material, acting as an electron donor, can achieve stable short-cut denitrification under normal conditions. It is easy to operate and control, and does not require maintaining high pH, ​​free ammonia, and free nitrite nitrogen levels in the wastewater.

[0028] 4. The nitrite nitrogen generated during short-cut denitrification using packing material as a microbial carrier can be further removed from wastewater by combining with anaerobic ammonium oxidation (ANAO). This achieves a suitable concentration of ANAO in the wastewater treatment plant effluent while reducing the aeration rate and external carbon source dosage in the upstream biological treatment process, thus lowering wastewater treatment costs. Specifically, wastewater effluent is primarily composed of nitrate nitrogen with a low ANAO concentration. Since ANAO requires ANAO in the influent, the aeration rate in the upstream process can be reduced to decrease nitrification efficiency, ensuring a certain concentration of ANAO in the effluent. This reduces the plant's operating energy consumption. Both the short-cut denitrification and ANAO processes using this packing material do not require external organic carbon sources, reducing reagent dosage costs and eliminating the risk of secondary pollution.

[0029] 5. During the short-cut denitrification process, the ferrous ions released by the ferrous sulfide in the packing material and / or the ferric ions generated during denitrification can form precipitates with orthophosphate in the wastewater, thereby removing total phosphorus from the wastewater.

[0030] 6. The packing material of this application achieves simultaneous deep denitrification and phosphorus removal of wastewater effluent by combining elemental sulfur with ferrous sulfide, and the effluent quality can reach or exceed Class IV standards in the surface water environmental quality standards. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a diagram illustrating the application scenario of a water treatment method in one embodiment;

[0033] Figure 2 This is a schematic diagram illustrating the process principle of a water treatment method in one embodiment;

[0034] Figure 3 This is another process principle diagram of the water treatment method in one embodiment. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0037] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the term "and / or" throughout the text includes three solutions; taking A and / or B as an example, it includes technical solution A, technical solution B, and a technical solution that simultaneously satisfies A and B. Furthermore, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of a person skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0038] This application provides a filler comprising elemental sulfur and ferrous sulfide in a mass ratio of (1.5 to 3):1.

[0039] refer to Figure 1 When the packing material of this application is placed in a reactor, activated sludge is then inoculated into the reactor to enrich and cultivate sulfur-autotrophic denitrifying bacteria, or denitrifying sludge containing sulfur-autotrophic denitrifying bacteria is directly inoculated so that the sulfur-autotrophic denitrifying bacteria attach to the surface of the packing material. Then, wastewater to be treated is injected into the reactor so that the sulfur-autotrophic denitrifying bacteria attached to the packing material use the packing material as an electron donor to perform short-cut denitrification of the wastewater, thereby converting nitrate nitrogen in the wastewater into nitrite nitrogen. At the same time, the ferrous ions released or the iron ions generated by the ferrous sulfide in the packing material during the short-cut denitrification process can react with orthophosphate in the wastewater to form precipitates, thereby achieving simultaneous phosphorus removal from the wastewater. In addition, after stable nitrite nitrogen is generated during the short-cut denitrification process, the nitrite nitrogen can provide a reaction substrate for the anaerobic ammonium oxidation process. Thus, when combined with the anaerobic ammonium oxidation process, the ammonia nitrogen in the wastewater can react with the above-mentioned nitrite nitrogen to form nitrogen gas, thereby achieving deep denitrification of the wastewater.

[0040] Therefore, the filler of this application has at least the following beneficial effects:

[0041] 1. This packing material, acting as an electron donor, stably achieves short-cut denitrification of low-concentration nitrate nitrogen and enables the accumulation of nitrite nitrogen;

[0042] 2. By combining anaerobic ammonia oxidation processes, efficient denitrification of low-concentration nitrogen-containing wastewater was achieved, providing a new and efficient solution for denitrification of wastewater treatment plant effluent;

[0043] 3. This packing material, acting as an electron donor, can achieve stable short-cut denitrification under normal conditions. It is easy to operate and control, and does not require maintaining high pH, ​​free ammonia, and free nitrite nitrogen levels in the wastewater.

[0044] 4. The nitrite nitrogen generated during short-cut denitrification using packing material as a microbial carrier can be further removed from wastewater by combining with anaerobic ammonium oxidation (ANAO). This achieves a suitable concentration of ANAO in the wastewater treatment plant effluent while reducing the aeration rate and external carbon source dosage in the upstream biological treatment process, thus lowering wastewater treatment costs. Specifically, wastewater effluent is primarily composed of nitrate nitrogen with a low ANAO concentration. Since ANAO requires ANAO in the influent, the aeration rate in the upstream process can be reduced to decrease nitrification efficiency, ensuring a certain concentration of ANAO in the effluent. This reduces the plant's operating energy consumption. Both the short-cut denitrification and ANAO processes using this packing material do not require external organic carbon sources, reducing reagent dosage costs and eliminating the risk of secondary pollution.

[0045] 5. During the short-cut denitrification process, the ferrous ions released by the ferrous sulfide in the packing material and / or the ferric ions generated during denitrification can form precipitates with orthophosphate in the wastewater, thereby removing total phosphorus from the wastewater.

[0046] 6. The packing material of this application achieves simultaneous deep denitrification and phosphorus removal of wastewater effluent by combining elemental sulfur with ferrous sulfide, and the effluent quality can reach or exceed Class IV standards in the surface water environmental quality standards.

[0047] (1) Principle of short-range denitrification reaction:

[0048] Short-cut denitrification refers to controlling the traditional full-process denitrification at the stage of nitrite nitrogen production, thus preventing nitrite nitrogen from being further reduced to nitrogen gas. Specifically, in the process of denitrification of wastewater using packing material, elemental sulfur and ferrous sulfide in the packing material serve as electron donors in the denitrification reaction. When the mass ratio of elemental sulfur to ferrous sulfide is in a suitable ratio (specifically 1.5:1 to 3:1), the contribution rate of elemental sulfur and ferrous sulfide to nitrogen removal is relatively stable, and the denitrification efficiency of wastewater is affected. The community structure of microorganisms and the abundance of functional genes of related enzymes are significantly altered, ultimately resulting in changes in enzyme activity. The activity of nitrate nitrogen reductase decreases slightly, while the activity of nitrite nitrogen reductase decreases significantly. Nitrate nitrogen is dominant in competing for electrons provided by sulfur oxidation, and the reduction of nitrite nitrogen is more inhibited, which reduces the conversion rate of nitrate nitrogen and the reduction rate of nitrite nitrogen decreases even more. The increased difference between the reduction rates of nitrate nitrogen and nitrite nitrogen will lead to the preferential reduction of nitrate nitrogen and the accumulation of nitrite nitrogen, thereby achieving short-cut denitrification of wastewater and converting nitrate nitrogen in wastewater into nitrite nitrogen.

[0049] 0.55S + NO3 - +0.325HCO3 - +0.065NH4 ++0.355H2O→

[0050] 0.55SO4 2- +0.065C5H7O2N+0.84H + +NO2 -

[0051] FeS + 1.228NO3 - +0.438HCO3 - +0.027CO2 +1.573H + +0.093NH4 + →

[0052] Fe 2+ +SO4 2- +0.093C5H7O2N+0.614N2+0.866H2O

[0053] (2) Phosphorus removal principle:

[0054] During the short-cut denitrification process, the ferrous ions released by the ferrous sulfide in the packing material and / or the ferric ions generated during denitrification can form precipitates with orthophosphate in the wastewater, thereby removing total phosphorus from the wastewater.

[0055] 3Fe 2+ +2PO4 3- =Fe3(PO4)2↓

[0056] Fe 3+ +PO4 3- =FePO4↓

[0057] 3. Principle of Anaerobic Ammonia Oxidation Process:

[0058] The principle of anaerobic ammonia oxidation denitrification is that, under anaerobic conditions, anaerobic ammonia oxidizing bacteria convert ammonia nitrogen and nitrite nitrogen in wastewater into nitrogen gas, thereby achieving wastewater denitrification.

[0059] NH4 + +1.32NO2 - +0.066HCO3 - +0.13H + →

[0060] 1.02N2 + 0.26NO3 - +2.03H₂O + 0.066CH₂O 0.5 N 0.15

[0061] This application also provides a method for preparing a filler, the method comprising the following steps:

[0062] S01. Mix elemental sulfur and ferrous sulfide powder in a mass ratio of (1.5 to 3):1 until homogeneous to obtain a powder mixture;

[0063] S02. Sinter the powder mixture at 115-150℃ for 20-30 minutes until elemental sulfur is in a molten state and uniformly coated with ferrous sulfide;

[0064] S03. The sintered molten filler is physically granulated and cooled to solidify into filler.

[0065] The method for preparing the filler provided in this application involves first mixing elemental sulfur and ferrous sulfide powder in a mass ratio of (1.5–3):1 to obtain a powder mixture; then sintering the powder mixture at 115–150°C for 20–30 minutes until the elemental sulfur is in a molten state and uniformly coated with ferrous sulfide; and finally granulating and cooling the molten filler to obtain the filler. Since the melting point of elemental sulfur is close to 115°C, and the melting point of ferrous sulfide is 1194°C, which is much higher than the melting point of elemental sulfur, during sintering at 115–150°C, the elemental sulfur melts into a molten state while the ferrous sulfide remains unchanged. The molten elemental sulfur acts as the skeleton of the filler, and the doped ferrous sulfide is fixed inside and on the surface of the filler after the molten elemental sulfur cools. The powder mixture is then cooled and shaped to obtain the filler of this application.

[0066] Optionally, in step S01, elemental sulfur and ferrous sulfide can be placed in a pulverizer for pulverization, and the particle size of the powder formed after pulverizing elemental sulfur and ferrous sulfide is less than 500 μm.

[0067] Preferably, the mass ratio of elemental sulfur to ferrous sulfide is 2:1. When the mass ratio of elemental sulfur to ferrous sulfide is too low, the contribution rate of elemental sulfur decreases, leading to a decrease in wastewater denitrification efficiency. When the mass ratio of elemental sulfur to ferrous sulfide is too high, the contribution rate of elemental sulfur increases, which is not conducive to the realization of short-cut denitrification. Elemental sulfur is the main contributor to denitrification, with a contribution rate of about 80%, while the contribution rate of ferrous sulfide is about 20%. According to the electron transfer calculation based on the biochemical equation, the mass ratio of elemental sulfur to ferrous sulfide is close to 2:1. This mass ratio of 2:1 is a theoretical calculation value. Therefore, the mass ratio of elemental sulfur to ferrous sulfide should be controlled at (1.5~3):1. At this ratio, the denitrification contribution rates of elemental sulfur and ferrous sulfide are stable, which is also conducive to maintaining the effect of short-cut denitrification.

[0068] There are various physical granulation methods for fillers. Optionally, physical granulation methods include any one of die extrusion cooling, rotary steel belt condensation granulation, tower air cooling granulation, direct water cooling granulation, and spray granulation. The particle size of the filler should be controlled to be less than or equal to 10 mm during granulation.

[0069] refer to Figure 1This application also provides a water treatment method, which includes the following steps:

[0070] S11. Provide the above-mentioned filler;

[0071] S12. Place the packing material in the reactor, and then inoculate the reactor with activated sludge to enrich and cultivate sulfur autotrophic denitrifying bacteria, or directly inoculate denitrifying sludge containing sulfur autotrophic denitrifying bacteria, so that the sulfur autotrophic denitrifying bacteria attach to the surface of the packing material.

[0072] S13. The wastewater to be treated is injected into the reactor so that the sulfur autotrophic denitrifying bacteria attached to the surface of the packing material can use the packing material as an electron donor to perform short-cut denitrification of the wastewater, converting nitrate nitrogen in the wastewater into nitrite nitrogen, thereby achieving the accumulation of nitrite nitrogen.

[0073] During the short-cut denitrification process, the ferrous ions released from the ferrous sulfide in the packing material and / or the ferric ions generated form precipitates with orthophosphate in the wastewater and are retained in the biofilm, thereby achieving the removal of total phosphorus from the wastewater.

[0074] In one embodiment, the water treatment method further includes:

[0075] S14. The wastewater after short-cut denitrification is subjected to anaerobic ammonia oxidation treatment. Under the action of anaerobic ammonia oxidizing bacteria, the nitrite nitrogen accumulated in the wastewater after short-cut denitrification and the ammonia nitrogen in the wastewater are simultaneously converted into nitrogen gas, so as to achieve efficient denitrification of low-concentration nitrogen-containing wastewater.

[0076] In summary, when the packing material of this application is placed in a reactor, and then activated sludge is inoculated into the reactor to enrich and cultivate sulfur-autotrophic denitrifying bacteria, or denitrifying sludge containing sulfur-autotrophic denitrifying bacteria is directly inoculated so that the sulfur-autotrophic denitrifying bacteria attach to the surface of the packing material; then, wastewater to be treated is injected into the reactor so that the microorganisms attached to the packing material can use the packing material to perform short-cut denitrification of the wastewater, thereby converting nitrate nitrogen in the wastewater into nitrite nitrogen; at the same time, the ferrous ions released and / or the iron ions generated by the ferrous sulfide in the packing material during the short-cut denitrification process can react with orthophosphate in the wastewater to form precipitates, thereby achieving simultaneous phosphorus removal from the wastewater; in addition, when stable nitrite nitrogen is generated during the short-cut denitrification process, this nitrite nitrogen can provide a reaction substrate for the anaerobic ammonium oxidation process. Thus, when combined with the anaerobic ammonium oxidation process, the ammonia nitrogen in the wastewater can react with the above-mentioned nitrite nitrogen to form nitrogen gas, thereby achieving deep denitrification of the wastewater.

[0077] In one embodiment, the activated sludge can be activated sludge in a secondary sedimentation tank or activated sludge in other biological treatment tanks; the denitrifying sludge containing sulfur-autotrophic denitrifying bacteria can be activated sludge or biofilm in a sulfur-autotrophic denitrifying biological treatment tank.

[0078] In one embodiment, the concentration ratio of ammonia nitrogen to nitrate nitrogen in the wastewater influent is 1:(1.5-2). Specifically, since nitrate nitrogen in the wastewater cannot be completely converted to nitrite nitrogen during short-cut denitrification, and the theoretical concentration ratio of nitrite nitrogen to ammonia nitrogen in the anaerobic ammonia oxidation process is 1.32:1, it is necessary to control the nitrate nitrogen concentration in the wastewater influent to be relatively higher. Therefore, by adjusting the water quality of the wastewater influent, the wastewater influent contains appropriate concentrations of ammonia nitrogen and nitrate nitrogen, wherein the concentration ratio of ammonia nitrogen to nitrate nitrogen is controlled at 1:(1.5-2). The adjusted wastewater enters the reactor, where sulfur-autotrophic denitrifying microorganisms use the packing material as an electron donor to perform short-cut denitrification treatment on the wastewater, converting nitrate nitrogen in the wastewater into nitrite nitrogen. For example, when the influent is the effluent from a wastewater treatment plant, the quality of the influent is mainly determined by adjusting the operating parameters of the upstream biological treatment process of the wastewater treatment plant. Specifically, this includes: reducing the aeration rate in the aerobic tank to obtain an appropriate concentration of ammonia nitrogen; and reducing the amount of organic carbon source added in the anoxic tank to obtain an appropriate concentration of nitrate nitrogen, so that the effluent from the wastewater treatment plant has appropriate concentrations of ammonia nitrogen and nitrate nitrogen, wherein the concentration of ammonia nitrogen is 10-15 mg / L and the concentration of nitrate nitrogen is 20-30 mg / L.

[0079] In one embodiment, the water treatment method includes a one-stage combined process or a two-stage combined process;

[0080] A single-stage combined process refers to the treatment of wastewater by short-cut denitrification and anaerobic ammonia oxidation in the same reactor. Short-cut denitrification converts nitrate nitrogen in wastewater into nitrite nitrogen, which is then removed by anaerobic ammonia oxidation along with ammonia nitrogen, achieving efficient nitrogen removal in the same reactor.

[0081] The two-stage combined process refers to the use of two reactors connected along the influent direction to treat wastewater through short-cut denitrification and anaerobic ammonia oxidation, respectively. The two reactors are defined as a short-cut denitrification reactor and an anaerobic ammonia oxidation reactor. The effluent from the short-cut denitrification reactor flows into the anaerobic ammonia oxidation reactor for anaerobic ammonia oxidation treatment, thereby achieving efficient nitrogen removal.

[0082] Specifically, refer to Figure 2When a single-stage combined process is adopted, i.e., when wastewater undergoes short-cut denitrification and anaerobic ammonia oxidation within the same reactor 100, the packing material is placed inside the reactor 100, and activated sludge is inoculated into the reactor 100. Sulfoautotrophic denitrifying bacteria and anaerobic ammonia oxidizing bacteria are enriched through acclimation and cultivation, or sludge containing these functional bacteria is simultaneously inoculated. In this way, within the reactor 100, nitrate nitrogen in the wastewater is converted to nitrite nitrogen through short-cut denitrification. The generated nitrite nitrogen is then rapidly removed simultaneously from the ammonia nitrogen in the wastewater through anaerobic ammonia oxidation. It should be noted that in the above-mentioned single-stage combined process, both elemental sulfur and ferrous sulfide in the packing material participate in short-cut denitrification. Elemental sulfur is the main contributor to nitrogen removal, with a contribution rate of approximately 80%, while ferrous sulfide contributes approximately 20%. Furthermore, during the short-cut denitrification process, the ferrous ions dissolved from ferrous sulfide and / or the generated iron ions can react with orthophosphate in the wastewater to form precipitates, thereby achieving simultaneous removal of total phosphorus from the wastewater.

[0083] The advantages of the aforementioned single-stage combined process include at least the following: by setting up a single reactor to simultaneously carry out short-cut denitrification and anaerobic ammonium oxidation processes, the footprint can be effectively reduced, the hydraulic retention time shortened, and the denitrification rate of wastewater increased. At the same time, the nitrite nitrogen generated during short-cut denitrification can be utilized in a timely manner. In addition, since short-cut denitrification will cause the pH of the water body to decrease, while anaerobic ammonium oxidation will cause the pH of the water body to increase, coupling the above-mentioned short-cut denitrification and anaerobic ammonium oxidation reactions in the same reactor is beneficial to maintaining the pH stability of the water body.

[0084] Optionally, in a single-stage combined process, anaerobic ammonia oxidation sludge is simultaneously inoculated within the same reactor, or auxiliary packing material loaded with anaerobic ammonia oxidation sludge is added, or the enrichment of anaerobic ammonia oxidation bacteria is achieved through acclimatization cultivation. Specifically, the auxiliary packing material can be any one of sponge, ceramsite, suspended packing material, braided biological packing material, geotextile, mesh, and volcanic rock.

[0085] refer to Figure 3When a two-stage combined process is adopted, that is, when two reactors 100 connected along the influent direction respectively perform short-cut denitrification and anaerobic ammonium oxidation treatment on wastewater, the two reactors 100 are defined as reactor 101 for short-cut denitrification and reactor 102 for anaerobic ammonium oxidation. The reactor 100 at the upstream end constitutes reactor 101 for short-cut denitrification, and the reactor 100 at the downstream end constitutes reactor 102 for anaerobic ammonium oxidation. The packing material is placed in reactor 101 for short-cut denitrification, and the treatment is carried out in both reactors 100. Sulfotrophic denitrifying sludge and anaerobic ammonia oxidation sludge are inoculated into reactors 1 and 102, or sulfurotrophic denitrifying bacteria and anaerobic ammonia oxidation bacteria are enriched and acclimated by inoculating activated sludge, respectively. In reactor 101 of short-cut denitrification, nitrate nitrogen in wastewater is converted into nitrite nitrogen through short-cut denitrification. The effluent from reactor 101 of short-cut denitrification enters reactor 102 of anaerobic ammonia oxidation. In reactor 102 of anaerobic ammonia oxidation, ammonia nitrogen and nitrite nitrogen in wastewater are removed through anaerobic ammonia oxidation under the action of anaerobic ammonia oxidation bacteria. In addition, in reactor 101 of short-cut denitrification, ferrous ions dissolved from ferrous sulfide in the packing material and / or ferric ions generated during short-cut denitrification react with orthophosphate in wastewater to form precipitates, thereby achieving simultaneous phosphorus removal from wastewater.

[0086] The advantages of the above two-stage combined process include at least the following: since the short-cut denitrification reaction and the anaerobic ammonium oxidation reaction are carried out in two separate reactors, the functional microorganisms in each reactor will not interfere with each other, thus increasing the system stability; in addition, the dissolved oxygen in the wastewater decreases after the short-cut denitrification, and the effluent from the short-cut denitrification can provide good low dissolved oxygen conditions for anaerobic ammonium oxidation, while also facilitating the backwashing of the packing material in the short-cut denitrification reactor separately.

[0087] Optionally, the two-stage combined process facilitates segmented backwashing of the packing material in the short-cut denitrification reactor 101. Optionally, in the two-stage combined process, the anammox reactor 102 can be, but is not limited to, any one of a packed bed, fluidized bed, contact oxidation reactor, MBR reactor, and MBBR reactor; the auxiliary packing material in the anammox reactor 102 can be any one of sponge, ceramsite, suspended packing material, braided biological packing material, geotextile, mesh, and volcanic rock.

[0088] Optionally, in the two-stage combined process, the anammox reactor 102 can be directly inoculated with anammox sludge or auxiliary packing material loaded with anammox sludge, or the anammox bacteria can be enriched by inoculating activated sludge and acclimating them.

[0089] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the invention. Any equivalent structural transformations made using the contents of the specification and drawings of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of patent protection of the present invention.

Claims

1. A water treatment method, characterized in that, Includes the following steps: A filler is provided, the filler comprising elemental sulfur and ferrous sulfide in a mass ratio of (1.5~3):1; The packing material is placed in the reactor, and then activated sludge is inoculated into the reactor to enrich and cultivate sulfur autotrophic denitrifying bacteria, or denitrifying sludge containing sulfur autotrophic denitrifying bacteria is directly inoculated so that the sulfur autotrophic denitrifying bacteria attach to the surface of the packing material. Wastewater to be treated is injected into the reactor so that sulfur-autotrophic denitrifying bacteria attached to the packing surface can use the packing as an electron donor to perform short-cut denitrification of the wastewater, converting nitrate nitrogen in the wastewater into nitrite nitrogen, thereby achieving the accumulation of nitrite nitrogen. During the short-range denitrification process, the ferrous ions released from the ferrous sulfide in the packing material or the ferric ions generated form precipitates with orthophosphate in the wastewater, thereby removing total phosphorus from the wastewater.

2. The water treatment method according to claim 1, characterized in that, The method for preparing the filler includes the following steps: S01. Mix elemental sulfur and ferrous sulfide powder in a mass ratio of (1.5~3):1 until homogeneous to obtain a powder mixture; S02. Sinter the powder mixture at 115~150℃ for 20~30 min until the elemental sulfur is in a molten state and uniformly coated with the ferrous sulfide; S03. The sintered molten filler is physically granulated and cooled to solidify to form the filler.

3. The water treatment method according to claim 2, characterized in that, The physical granulation method includes any one of the following: die extrusion cooling, rotary steel strip condensation granulation, tower air cooling granulation, direct water cooling granulation, and spray granulation.

4. The water treatment method according to claim 1, characterized in that, Also includes: Wastewater treated by short-cut denitrification is subjected to anaerobic ammonia oxidation treatment. Under the action of anaerobic ammonia oxidizing bacteria, the nitrite nitrogen accumulated in the wastewater after short-cut denitrification and the ammonia nitrogen in the wastewater are simultaneously converted into nitrogen gas, so as to achieve efficient denitrification of low-concentration nitrogen-containing wastewater.

5. The water treatment method according to claim 4, characterized in that, The concentration ratio of ammonia nitrogen to nitrate nitrogen in the wastewater influent is 1:(1.5~2).

6. The water treatment method according to claim 4, characterized in that, The water treatment method includes a single-stage combined process or a two-stage combined process; The aforementioned one-stage combined process refers to: short-cut denitrification and anaerobic ammonium oxidation of wastewater within the same reactor; Short-cut denitrification converts nitrate nitrogen in wastewater into nitrite nitrogen, which is then removed together with ammonia nitrogen by anaerobic ammonia oxidation, achieving efficient nitrogen removal in the same reactor. The two-stage combined process refers to the following: wastewater is treated by short-cut denitrification and anaerobic ammonia oxidation in two reactors connected along the influent direction. The two reactors are defined as a short-cut denitrification reactor and an anaerobic ammonia oxidation reactor, respectively. The effluent from the short-cut denitrification reactor flows into the anaerobic ammonia oxidation reactor for anaerobic ammonia oxidation treatment, thereby achieving efficient nitrogen removal.

7. The water treatment method according to claim 6, characterized in that, In the aforementioned one-stage combined process, anaerobic ammonia oxidation sludge is simultaneously inoculated in the same reactor, or auxiliary packing material loaded with anaerobic ammonia oxidation sludge is added, or anaerobic ammonia oxidation bacteria are enriched through acclimatization cultivation.

8. The water treatment method according to claim 7, characterized in that, The auxiliary filler is any one of sponge, ceramsite, suspended filler, braided biological filler, geotextile, mesh, and volcanic rock.

9. The water treatment method according to claim 6, characterized in that, In the two-stage combined process, the anaerobic ammonia oxidation reactor includes any one of a packed bed, a fluidized bed, a contact oxidation reactor, an MBR reactor, and an MBBR reactor.

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